The invention is particularly well suited for use in treating tire cord fabric, especially fabric having warp cords composed of nylon, polyester, or metal. It is desirable coating such tire cords with a substance or agent which promotes the bond between the cords and rubber material used in the production of tires. One such method advantageously employs a liquid solvent as a carrier for bringing the bonding agent into contact with the warp cords. This particular method has never been used to a great extent in the past, because of the high cost of the solvent and the inability to recapture the solvent after deposition of the agent on the warp cords. In some known processes, the tire cord fabric is dipped in a liquid mixture of solvent and agent and then passed into a chamber, filled with solvent vapor, where the fabric contacts hot cans or heated rollers for vaporizing the solvent, carried by the fabric, to dry the fabric. The vaporized solvent is then removed and reconditioned for reuse in the process. Impurities in the solvent mixture react unfavorably when the fabric contacts the hot cans, causing undesirable deposits on the hot cans, necessitating frequent stoppage of the process to clean or replace the contaminated hot cans.
Other methods, more suitable for treating tire cord fabric on a production basis, employ super-heated solvent vapor, rather than hot cans, for contacting the fabric to heat and evaporate the solvent. It has been found that using the latter method increases the rate at which the fabric can be processed which, from an economical standpoint, is very important. Although the use of super-heated solvent vapor produces beneficial results, a highly efficient apparatus for treating the fabric and recovering solvent vapor has not been found. The invention is directed to providing such an apparatus.
Briefly stated, the invention is in an apparatus for treating tire cord fabric. Means are provided for coating the tire cord fabric with a liquid coating comprising a mixture of an agent which promotes the bond between the warp cords of the fabric and rubber material used in the production of tires, and a vaporizable solvent which is a carrier of the agent. A drying chamber is supplied adjacent the fabric coating means and is sealed from the ambient atmosphere and said means. The drying chamber has inlet and outlet openings through which the tire cord fabric passes as it moves into and out of the drying chamber. A condenser is disposed adjacent each of the openings for condensing excess solvent vapor in the drying chamber. Means are provided for filling the drying chamber with a vapor of a solvent similar to the solvent of the mixture. A plurality of vertically elongated plenums are disposed side-by-side in the drying chamber, and a number of vertically spaced nozzles extend from each of the plenums for directing superheated vapor of a solvent, similar to the solvent of the mixture, against tire cord fabric guided past the nozzles. Means are provided for continually removing solvent as a vapor from the drying chamber, and superheating the removed solvent vapor for subsequent passage through the nozzles. Also provided are means for removing the condensed solvent vapor from the drying chamber for reconditioning and reuse in the process, such reconditioning including separating condensed solvent from impurities, such as water, and reusing the purified solvent in a new mixture.